The father and mother have a 4 blood group. My son has a -2 group. Is this their son

The father and mother have a 4 blood group. My son has a -2 group. Is this their son, and what blood groups can there be children with?

Given;
mother – IV blood group
father – IV blood group
son – II blood group

Find: does the son belong to the specified pair, possible blood types of the offspring

Decision:
Based on the inheritance of blood groups of the AB0 system, it becomes known that the presence of a certain blood group is determined by a pair of genes (loci), each of which can be in three states (jA, jB or j0). Genotypes and phenotypes of individuals with different blood groups: I (0) group – j0j0, II (A) group – jAjA, jAj0, III (B) group – jBjB, jBj0, IV (AB) group – jAjB.
Consider a pair: one and the other parent have IV blood group – genotype jAjB.
The table shows that the offspring of this pair can be of three blood groups: II (A) group – jAjA, III (B) group – jBjB, IV (AB) group – jAjB.
Answer: a boy with II (A) group is the son of a couple with IV blood group.